Re: [PATCH 1/2] slab: __GFP_ZERO is incompatible with a constructor

On Tue, 10 Apr 2018, Matthew Wilcox wrote:

__GFP_ZERO requests that the object be initialised to all-zeroes, while the purpose of a constructor is to initialise an object to a particular pattern. We cannot do both. Add a warning to catch any users who mistakenly pass a __GFP_ZERO flag when allocating a slab with a constructor.

Can we move this check out of the critical paths and check for a ctor and GFP_ZERO when calling the page allocator? F.e. in allocate_slab()?